CHALICOTHERIUMChalicotherium was an early, herbivorous mammal from the Miocene. This forest browser was an ungulate with large, clawed feet (instead of hooves). It may have been able to rear up on its hind legs to eat leaves high up in trees. Fossils have been found in Europe (Kazakhstan). Classification: Suborder Ancylopoda, Family Chalicotheriidae.

CHALIMIAChalimia was a tetrapod that lived during the late Triassic period. It was a tritheledontid cynodont (a synapsid, the group that led to the mammals). This amniote was not a dinosaur. Fossils have been found in the Los Colorados Formation in NW Argentina.

CHALKChalk is a soft, white type of limestone (a sedimentary rock). It consists mostly of calcium carbonate (CaCO3) from ancient, microscopic, single-celled marine invertebrate shells. This type of rock is very porous, soft (a hardness of 3 on the Mohs scale), and crumbly. The chalk used to draw with is actually gypsum (calcium sulfate, CaSO4-2H2O)

CHAMPSOSAUR(pronounced CHAMP-so-SAWRS) Champsosaurs were early lizard-like reptiles that lived in water. (Subclass Diapsida, Order Choristodera)

CHAMPSOSAURUS(pronounced CHAMP-so-SAWR-us) Champsosaurus was a long-jawed early reptile, a champsosaur that lived during the late Cretaceous period through the Eocene period. This fish-eater was about 5 feet (1.5 m) long, and lived in rivers and swamps. It had powerful jaws in a very long, thin, toothed snout, four short legs, and a long tail which it used to propel itself in the water. Fossils have been found in Europe and North America. It was not a dinosaur. (Subclass Diapsida, Order Choristodera)

CHANGTUSAURUSChangtusaurus (also called Changdusaurus, Chendusaurus, and Chengdusaurus) was a stegosaurid dinosaur that lived during the late Jurassic period. This plant-eater walked on four columnar legs. It had plates running along its back, spikes on its tail and no tail club. Fossils were found in the Changdu basin in China. The type species is C. laminaplacodus. Changtusaurus was named by Zhao in 1983 Very little is known about this genus.

CHANARESUCHUSChanaresuchus (meaning "Chañares [the formation in Argentina in which it was found] crocodile") was a small archosaur that lived during the mid Triassic Period, toughly 225 million years ago. This quadruped diapsid was about 3.5 feet (1 m) long, had teeth set into sockets, a pointed snout, and a very long tail. Chanaresuchus was not a dinosaur, but another type of archosaur.

CHARACTERA character is a inherited trait of an organism. Characters are usually described in terms of a state, for example: "blue eyes" vs. "brown eyes," where "eyes" is the character, and "blue" and "brown" are its states.

CHARONOSAURUS(pronounced shar-OWN-oh-SAWR-us) Charonosaurus was a long-crested, duck-billed dinosaur that lived during the very late Cretaceous period. This beaked plant-eater is known only from a partial skull found in the Yuliangze Formation in China.. The type species is P. jiayinensis; it was named by Godefroit, Zan and Jin in 2000. Charonosaurus means"Charon's lizard" Charon was the person in Greek mythology who ferried people over the river Styx on their way to hell.

CHASMATOSAURUS(pronounced kas-MAT-oh-SAWR-us) Chasmatosaurus (formerly known as Proterosuchus) is the earliest-known Proteroschian, a very primitive thecodont that lived during the early Triassic period, about 250 million years ago. This socket-toothed, carnivorous reptile had a low-slung body, long jaws with backwards-facing teeth, a sprawling gait, four short legs with five toes on each foot, and a long tail. Its upper jaw turned down at the tip. It had teeth on its palate (a primitive feature). It was about 6.5 ft (2 m) long. This archosaur was an ancestor of the dinosaurs. Chasmatosaurus may have hunted herbivorous Dicynodonts like Lystrosaurus on land but may have also hunted fish in the water. Fossils have been found in China and South Africa. Classification: Suborder Archosauria, Order Thecodontia, Suborder Proterosuchia, Genus Chasmatosaurus

CHASMOSAURUS(pronounced KAS-mo-SAWR-us) Chasmosaurus was a rhinoceros-like dinosaur that was 16-26 feet (5-8 m) long and weighed about 3.5 tons (3220 kg). Its femur (thigh bone) was 75 cm long. It was a three horned, plant-eating, frilled ceratopsian dinosaur that lived late in the late Cretaceous period, about 76 to 70 million years ago. The type species is C. belli.

CHEEK TEETHCheek teeth are teeth that are in the cheek area of the mouth, like molars and premolars in mammals. Duck-billed dinosaurs had cheek teeth.

CHELONIA(pronounced chee-LOW-nee-an) Chelonians (order Testudines) include the turtles, tortoises, and terrapins. These reptiles have a shell that encloses the body and a solid-roofed skull. The earliest chelonians date from the late Triassic period, over 200 million years ago. Classification:

Kingdom Animalia (animals)

Phylum Chordata

Subphylum Vertebrata (vertebrates)

Superclass Tetrapods (four limbs)

Class Reptilia (reptiles)

Subclass Anapsida

Order Testudines (=chelonia: turtles, tortoises, and terrapins).

CHICXULUB CRATERThe Chicxulub crater at the tip of the Yucatán Peninsula is an impact crater that dates from 65 million years ago. It is 120 miles wide and 1 mile deep. It is probably the site of the K-T meteorite impact that caused the extinction of the dinosaurs and other groups of organisms.

CHIALINGOSAURUS(pronounced CHEE-ah-LING-ah-SAWR-us) Chialingosaurus (meaning "Chialing [a river in China] lizard") was a dinosaur with a narrow skull. It was a stegosaurid that had plates and spikes on its back. This plant-eater lived during the middle Jurassic period, about 163-150 million years ago. It may have been up to 13 feet (4 m) long, weighing perhaps 150 kg. Its femur (thigh bone) was 69 cm long. Very incomplete fossils of this quadrupedal were found in China. It was named by paleontologist Hu in 1964. The type species is C. kuani.

CHIAPPE, LUISLuis M. Chiappe is a vertebrate paleontologist, Chairman of the Department of Vertebrae and Paleontology, and Associate Curator of the Natural History Museum of Los Angeles County. Chiappe has studied dinosaurs and the origins of birds. In 1997, Chiappe discovered a cache of thousands of 80-million-year-old fossilized titanosaur eggs at Auca Mahuevot in Patagonia, Argentina (titanosaurs are huge, long-necked, plant-eating dinosaurs). Many of the eggs contained fossilized dinosaur embryos. Chiappe wrote the books, "Tiniest Giants" (2001) and "SuperCroc" (2001).

CHILANTAISAURUS(pronounced chee-LAWN-ti-SAWR-us) Chilantaisaurus was a large theropod (probably an Allosaurid) dinosaur from the early Cretaceous period, about 113 to 97 million years ago. It may have been up to 10 feet (3 m) long, weighing perhaps up to 4 tons. It had enormous arms and very large claws; the first finger had a huge, upwards-curving, killer claw. The upper leg bone was longer than the lower leg bone and the toes were short (with unfused toe bones); these features indicate that Chilantaisaurus was not that fast a runner. Incomplete fossils of this bipedal meat-eater were found in Inner Mongolia, China and Siberia, Russia. It was named by paleontologist Hu in 1964; it was named after lake Chilantai in Mongolia). The type species is C. tashuikouensis.

CHIN, KARENKaren Chin is a paleontologist and ichnologist (studying trace fossils - coprolites in particular). In 1998, Dr. Chin studied the first fossilized T. rex dung (coprolites) that contained bits of Triceratops frill. She has also found traces of dung beetle tunnels in another dinosaur coprolite. Chin received her Masters Degree from Montana State University (working with Jack Horner), and her Ph.D. from University of California, Santa Barbara (in 1996).

CHIMERA(pronounced ki-MEER-eh) A chimera is a fossil that is composed of more than one species. Chimeras were named for a mythological, fire-breathing monster that had a lions' head, a goat's body, and a snake's tail.

CHINDESAURUS(pronounced CHIN-dee-SAWR-us) Chindesaurus (meaning "Chinde point lizard") was a theropod dinosaur about 6.5 feet (2 m) long, weighing about 65 pounds (30 kg). This fast-moving biped lived in what is now Arizona and New Mexico, USA, during the late Triassic period, roughly 220 million years ago. It was named by Murray and Long in 1985. It is known from a partial skeleton and teeth. The type species is C. bryansmalli.

CHINGKANKOUSAURUSChingkankousaurus (meaning "Ch'ing-kang-kou [village in Shandong Province] lizard") was an tetanuran or tyrannosaurid theropod dinosaur. This large meat-eater weighed roughly 5700 kg. It lived during the late Cretaceous period, about 88.5-65 million years ago. Only a fossilized right scapula (shoulder bone) was found in China. The type species is C. fragilis. Chingkankousaurus was named by paleontologist Young in 1958.

CHIROSTENOTES(pronounced KIE-roh-STEN-oh-teez) Chirostenotes (meaning "narrow hand") was an oviraptorid theropod dinosaur with a parrot-like head, toothless beak, long legs, and long, narrow fingers. This meat-eater was 5.5-6.5 ft (1.7-2 m) long and weighed roughly 35 kg. It lived during the late Cretaceous period. Partial fossils were found in Alberta, Canada. The type species is C. pergracilis. Chirostenotes was named by paleontologist Gilmore in 1924.

CHLAMYDOSAURUSChlamydosaurus (meaning "caped lizard") is a rare, modern-day frilled lizard (not a dinosaur) native to New Guinea and North Australia. Its frill is 7 - 14 inch (18-34 cm) flap of skin that completely circles its head. It opens this brightly-colored frill to frighten enemies. Adults are over 8 inches (20 cm) long. These climbing lizards live in trees in humid forests and eat cicadas, ants, spiders and smaller lizards. It can run quadrupedally and bipedally, with the front legs off the ground. Adult females lay 8 to 14 eggs per clutch in Spring and Summer. Classification: Class Reptilia, Order: Squamata, Family: Agamidae, Genus Chlamydosaurus, Species kingii (named by Gray in 1825).

CHONDRITIC METEORChondritic meteors are stony meteors with chondrules, tiny glass spheres. These meteors are unchanged since their formation, shortly after the formation of the sun. These meteors consist of elements also common in the Earth's core.

CHONDROSTEOSAURUS(pronounced kon-DROS-tee-oh-SAWR-us) Chondrosteosaurus (meaning "cartilage bone lizard") was a sauropod dinosaur (perhaps a Camarasaurid) with a long neck, long tail, and bulky body. This plant-eater was perhaps 58 ft (18 m) long and weighed roughly 25000 kg. It lived during the early Cretaceous period, 131-119 million years ago. Two neck vertebrae were found on England's Isle of Wight. The type species is C. gigas. Chondrosteosaurus was named by paleontologist R. Owen in 1876. Chondrosteosaurus is a dubious genus.

CHORDATAChordates are animals that have a notochord and gill clefts at some point in their life. They have a hollow nerve cord that ends in a brain. Chordates include the vertebrates, cephalochordates (e.g. amphioxus), and urochordates (e.g. sea squirts).

CHUBUTISAURUS(pronounced shoe-BOO-tee-SAWR-us) Chubutisaurus (meaning "Chubut [Province, Argentina] lizard") was an early titanosaurid sauropod dinosaur with a long neck, long tail, and bulky body with a humped back. This armored plant-eater was perhaps 75 ft (23 m) long and weighed roughly 39324 kg. It lived during the early Cretaceous period, 113-97 million years ago. Two parital skeletons were found in Argentina. The type species is C. insignis. Chubutisaurus was named by paleontologist del Corro in 1974.

CHUNGKINGOSAURUS(pronounced chung-KING-oh-SAWR-us) Chungkingosaurus (meaning "Chingking [a city in Sichuan Province, China] lizard") was a stegosaurid dinosaur. This plated, quadrupedal plant-eater was about 12 ft (3.5 m) long and weighed roughly 100 kg. It lived during the late Jurassic period, 163-150 million years ago. Partial skeletons were found in China. The type species is C. jiangbeiensis. Chungkingosaurus was named by paleontologists Dong, Zhou, and Zhang in 1983.